And at least a dozen more somewhat obscure high average temperature records -- for the 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 months ending in March 2012, as well as the warmest 12 consecutive months irrespective of ending month. I believe that the March 2012 number is now finalized at 56.7 degrees, beating the 1945 record by 0.5 degrees. Additionally: February-March 2012 averaged 50.5* degrees, beating the 1976 record by 1.4; January-March 2012 averaged 47.2 degrees, beating the 1990 record by 0.9; December 2011-March 2012 averaged 46.7 degrees, beating the 2001/2002 record by 2.3; November 2011-March 2012 averaged 47.8 degrees, beating the 2001/2002 record by 1.4; October 2011-March 2012 averaged 49.6 degrees, beating the 2001/2002 record by 0.9; September 2011-March 2012 averaged 52.7 degrees, beating the 1931/1932 record by 0.8; August 2011-March 2012 averaged 56.1 degrees, beating the 1973/1974 record by 0.8; July 2011-March 2012 averaged 59.3 degrees, beating the 1973/1974 record by 1.4; June 2011-March 2012 averaged 61.2 degrees, beating the 1973/1974 record by 1.3; May 2011-March 2012 averaged 61.9 degrees, beating the 2007/2008 record by 1.5; and April 2011-March 2012 averaged 61.6 degrees, beating the 1980/1981 record by 1.7. The last record is particularly noteworthy, because it is also the highest temperature for any 12-month period in DC history, beating the October 1990-September 1991 record by 0.8. Of course, this new 12-month record may be short-lived, if the April 2012 average temperature exceeds the April 2011 average of 58.8 degrees.
* Averages for more than one month (such as December, January, and February -- the three months of meteorological winter) have traditionally been calculated by assuming that each month has the same number of days, even though that method is slightly inaccurate because the months differ in length. For example, to calculate a true February-March 2012 average, the average temperature for each of those 60 days (29 in February and 31 in March) should be summed and divided by 60, rather than simply adding the average February temperature to the average March temperature and dividing by two. The true average for February-March 2012 is 50.8, rather than 50.5, but for consistency with traditional calculations, I have used the simpler method. Either way you do the calculations, all the above records were broken.